The Rome II pediatric criteria for functional gastrointestinal disorders (FGIDs) were defined in 1999 to be used as diagnostic tools and to advance empirical research. In this document, the Rome III Committee aimed to update and revise the pediatric criteria. The decision-making process to define Rome III criteria for children aged 4-18 years consisted of arriving at a consensus based on clinical experience and review of the literature. Whenever possible, changes in the criteria were evidence based. Otherwise, clinical experience was used when deemed necessary. Few publications addressing Rome II criteria were available to guide the committee. The clinical entities addressed include (1) cyclic vomiting syndrome, rumination, and aerophagia; 2) abdominal pain-related FGIDs including functional dyspepsia, irritable bowel syndrome, abdominal migraine, and functional abdominal pain; and (3) functional constipation and non-retentive fecal incontinence. Adolescent rumination and functional constipation are newly defined for this age group, and the previously designated functional fecal retention is now included in functional constipation. Other notable changes from Rome II to Rome III criteria include the decrease from 3 to 2 months in required symptom duration for noncyclic disorders and the modification of the criteria for functional abdominal pain. The Rome III child and adolescent criteria represent an evolution from Rome II and should prove useful for both clinicians and researchers dealing with childhood FGIDs. The future availability of additional evidence-based data will likely continue to modify pediatric criteria for FGIDs.